[Bug 59436] New: Wayland/EGL: Washed-out colors caused by double sRGB conversion on default framebuffer (GL_FRAMEBUFFER_SRGB)

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=59436

            Bug ID: 59436
           Summary: Wayland/EGL: Washed-out colors caused by double sRGB
                    conversion on default framebuffer
                    (GL_FRAMEBUFFER_SRGB)
           Product: Wine
           Version: 11.3
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winewayland
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 80417
  --> http://bugs.winehq.org/attachment.cgi?id=80417
Patch

Fixes https://bugs.winehq.org/show_bug.cgi?id=59073


Summary

When running Wine with the Wayland driver (winewayland.drv) using EGL, colors
may appear washed out / desaturated in OpenGL applications.
The issue is caused by GL_FRAMEBUFFER_SRGB remaining enabled while rendering to
the default framebuffer (FBO 0), leading to a double gamma/sRGB conversion in
some Wayland/EGL pipelines.

Disabling GL_FRAMEBUFFER_SRGB only when rendering to the default framebuffer
fixes the color output.


Environment

Wine: wine-git (tested on 11.x, reproducible on current master)

Backend: winewayland.drv (Wayland native, not XWayland)

GPU: AMD (Mesa)

Compositor: wlroots-based (qtile Wayland)

EGL backend in use

Application tested: Roon (Chromium/CEF-based UI, OpenGL rendering)

Observed behavior

Colors appear faded / washed out

Gamma looks incorrect (as if double sRGB conversion occurs)

Issue only occurs under Wayland/EGL

Colors are correct:

Under X11/XWayland

Or if GL_FRAMEBUFFER_SRGB is manually disabled for FBO 0


Root cause hypothesis

Some Wayland/EGL compositors already perform colorspace handling for the window
surface.
If GL_FRAMEBUFFER_SRGB remains enabled when rendering to the default
framebuffer, the pipeline applies sRGB conversion twice:

App → GL_FRAMEBUFFER_SRGB → EGL/Compositor colorspace → Display

This results in desaturated output.

Minimal fix

Disable GL_FRAMEBUFFER_SRGB only when binding the default framebuffer (FBO 0),
while preserving the application's requested sRGB state for non-default FBOs.


Example patch (conceptual)

Inside framebuffer binding path:

if (!framebuffer && gl_info->supported[ARB_FRAMEBUFFER_SRGB])
{
    TRACE("glBindFramebuffer disabling GL_FRAMEBUFFER_SRGB on default
framebuffer\n");
    glDisable(GL_FRAMEBUFFER_SRGB);
}
else if (framebuffer && app_framebuffer_srgb_enabled)
{
    TRACE("glBindFramebuffer restoring GL_FRAMEBUFFER_SRGB on non-default
framebuffer\n");
    glEnable(GL_FRAMEBUFFER_SRGB);
}


Results

Colors become correct under Wayland/EGL

No regression observed in tested OpenGL apps

Behavior matches X11 output

sRGB still works correctly for offscreen FBO rendering

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[Bug 59436] Wayland/EGL: Washed-out colors caused by double sRGB conversion on default framebuffer (GL_FRAMEBUFFER_SRGB)

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=59436

--- Comment #1 from tpaniaki <[e-mail]> ---
Comment on attachment 80417
  --> http://bugs.winehq.org/attachment.cgi?id=80417
Patch

wrong_upload

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[Bug 59436] Wayland/EGL: Washed-out colors caused by double sRGB conversion on default framebuffer (GL_FRAMEBUFFER_SRGB)

[WineHQ Bugzilla]

http://bugs.winehq.org/show_bug.cgi?id=59436

--- Comment #2 from tpaniaki <[e-mail]> ---
Comment on attachment 80417
  --> http://bugs.winehq.org/attachment.cgi?id=80417
Patch
> diff --git a/dlls/opengl32/thunks.c b/dlls/opengl32/thunks.c
> index 3c60ec5d6bb..7145c2c1b7f 100644
> --- a/dlls/opengl32/thunks.c
> +++ b/dlls/opengl32/thunks.c
> @@ -3207,8 +3207,45 @@ static void WINAPI glBindFramebuffer( GLenum target, GLuint framebuffer )
> {
>     struct glBindFramebuffer_params args = { .teb = NtCurrentTeb(), .target = target, .framebuffer = framebuffer };
>     NTSTATUS status;
> +    static BOOL srgb_disabled_for_default_fb;
> +
>     TRACE( "target %d, framebuffer %d\n", target, framebuffer );
>     if ((status = UNIX_CALL( glBindFramebuffer, &args ))) WARN( "glBindFramebuffer returned %#lx\n", status );
> +
> +    if (target == GL_DRAW_FRAMEBUFFER || target == GL_FRAMEBUFFER)
> +    {
> +        struct glIsEnabled_params is_enabled_args = { .teb = NtCurrentTeb(), .cap = GL_FRAMEBUFFER_SRGB };
> +        GLboolean srgb_enabled;
> +
> +        if ((status = UNIX_CALL( glIsEnabled, &is_enabled_args ))) WARN( "glIsEnabled returned %#lx\n", status );
> +        srgb_enabled = is_enabled_args.ret;
> +
> +        if (!framebuffer)
> +        {
> +            /* Avoid double sRGB/gamma conversion on the onscreen framebuffer. */
> +            if (srgb_enabled)
> +            {
> +                struct glDisable_params disable_args = { .teb = NtCurrentTeb(), .cap = GL_FRAMEBUFFER_SRGB };
> +
> +                TRACE( "disabling GL_FRAMEBUFFER_SRGB on default framebuffer\n" );
> +                if ((status = UNIX_CALL( glDisable, &disable_args ))) WARN( "glDisable returned %#lx\n", status );
> +                srgb_disabled_for_default_fb = TRUE;
> +            }
> +            else
> +            {
> +                srgb_disabled_for_default_fb = FALSE;
> +            }
> +        }
> +        else if (srgb_disabled_for_default_fb)
> +        {
> +            /* Restore sRGB state for offscreen FBOs if we disabled it for FBO 0. */
> +            struct glEnable_params enable_args = { .teb = NtCurrentTeb(), .cap = GL_FRAMEBUFFER_SRGB };
> +
> +            TRACE( "restoring GL_FRAMEBUFFER_SRGB on non-default framebuffer\n" );
> +            if ((status = UNIX_CALL( glEnable, &enable_args ))) WARN( "glEnable returned %#lx\n", status );
> +            srgb_disabled_for_default_fb = FALSE;
> +        }
> +    }
> }
>
> static void WINAPI glBindFramebufferEXT( GLenum target, GLuint framebuffer )

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